Posada, sidelined since straining his right hamstring while sliding during a May 4 game against Boston, took batting practice, threw and participated in a running program on Monday.
"Maybe Wednesday or Thursday," Posada said after working out at the Yankees' minor league complex. "It's now a matter of getting into baseball shape."
Outfielder Xavier Nady (right elbow ligament), catcher Jose Molina (strained left quadriceps) and third baseman Cody Ransom (right quadriceps) worked out with Posada. All three also took part in the running session.
Nady could be the designated hitter during a minor league game in the next couple days, and Molina might be ready by late this week.
Also, left-handed reliever Damaso Marte, out with left shoulder tendinitis, has resumed throwing on level ground.
Right-hander Sergio Mitre, coming back from right elbow ligament replacement surgery, threw four innings in an extended spring training game against Philadelphia minor leaguers. Playing for the Phillies was catcher Paul Bako, who agreed to a minor league contract with the team last week.
The Yankees also announced Monday, before their road game against the Texas Rangers, that right-handed reliever Brian Bruney has been put back on the disabled list because of a recurring right elbow strain.
Bruney, who pitched only once since being activated Tuesday from the DL, played catch Monday but said his arm doesn't feel right.